The city’s police union is having a hard time swallowing givebacks in exchange for 10 percent raises over two years, sources said yesterday.

Arbitrator Eric Schmertz is prepared to award the double-digit retroactive raise, but he hasn’t been able to convince the Patrolmen’s Benevolent Association to go along with a series of givebacks, the sources said.

They include: reduced pay for recruits in the Police Academy; stretching out the pay ladder from six to seven years; the loss of one personal day a year and allowing the NYPD to change schedules without overtime on 15 occasions a year instead of 10.

Those givebacks would reduce the cost to the city of the entire package, possibly by a significant amount.

“If the net value is above 8 percent for two years, [the cops are] getting a pretty decent settlement,” observed one labor expert not involved in the negotiations.

“The contracts I’m doing now are in the 3 to 4 [percent] range. If they get the top of the range, they’re doing well.”

The PBA, which has invested millions in the seven-month arbitration proceedings, is on the verge of breaking the pattern set earlier by civilian unions.

Those unions settled for little more than 5 percent over three years.

The three-member arbitration panel includes Schmertz, who is the “neutral” party, and one arbitrator appointed by the PBA and one by the city.

To make an award, Schmertz needs the vote of at least one of the other two arbitrators.

One city official estimated it would cost $70 million to fund each percentage point in raises, or $700 million for all uniformed workers.

The last PBA contract expired July 31, 2002. Cops now start at $34,514 and max out at $60,818 after 21 years.

One police source said veteran cops are clamoring for long overdue retroactive checks averaging $12,000.